The iconic dinosaur faunas of the Late Jurassic and Late Cretaceous of western North America have been studied for over a century. Late Jurassic dinosaur communities contain famous long neck dinosaurs (sauropods) like Brachiosaurus, plated dinosaurs (e.g., Stegosaurus), and familiar large predators (e.g., Allosaurus, Ceratosaurus). Likewise, Late Cretaceous dinosaur communities contain a fair number of other icons including tyrannosaurs (e.g., T. rex), dromaeosaurs (similar to Velociraptor), duckbill dinosaurs (e.g., Parasaurolophus), and horned dinosaurs (e.g., Triceratops).
Several of our current field projects seek to identify the dinosaurs that lived and died in between these two well known intervals during a time we informally call the “mid-Cretaceous”. Previous hypotheses have suggested that Late Jurassic dinosaur communities died out and were replaced by immigrant dinosaurs from Asia, via a newly formed land bridge between the two continents during the Early Cretaceous. If true than these new dinosaurs with Asian ties established themselves in western North America and redefined dinosaur communities on the continent for the next 40 million years or so, ultimately giving rise to the famous dinosaurs of the Late Cretaceous.
Project Goals and Target Formations
Each year our team from the North Carolina Museum of Natural History returns to several areas out west to fill in the biodiversity gaps of the mid-Cretaceous. Our expeditions take us to Utah to hunt for new dinosaurs in the Upper Cretaceous (Cenomanian, ~98 Ma) Mussentuchit Member of the Cedar Mountain Formation, in collaboration with our friends at the Field Museum of Natural History. So far our joint teams have discovered at least four new species of dinosaurs, including one of the largest predatory dinosaurs ever to roam North America – Siats meekerorum, North America’s tiniest tyrannosaur – Moros intrepidus, a giant oviraptorosaurian, and two new plant eating dinosaur species including an orodromine and an iguanodontian.
We also launch annual expeditions to New Mexico. In 2016 we began searching the Upper Cretaceous (Turnonian) Moreno Hill and Crevasse Canyon Formations for new species in partnership with The White Mountain Dinosaur Exploration Center. These sediments were deposited around six million years after the Mussentuchit ecosystem died out in Utah. From here we have collected the remains of ancient turtles, crocs, and several species of dinosaurs.